

ABSTRACT

Elastic, open-cell polyurethane soft block foams are produced by reacting a) polyisocyanates of the tolylene diisocyanate and/or hexamethylene diisocyanate and/or isophorone diisocyanate type with b) compounds containing at least two hydrogen atoms which are active toward isocyanates, having a molecular weight of from 400 to 10,000, and, if desired, c) chain extenders and crosslinking agents containing at least two hydrogen atoms which are active toward isocyanates, having a molecular weight of 32 - 399, in the presence of d) water as a blowing agent in an amount of 5-15 parts by weight, based on 100 parts by weight of component b), and, if desired, in the presence of e) other blowing agents, catalysts and further assistants and additives which are known per se, the reaction of all the components being carried out at a characteristic number of less than 80, preferably 40-65.



